Gas delivery systems for semiconductor processing equipment are the subject of stringent safety regulations. For example, SEMI Spec. S2-93, as well as various local ordinances, require that Hazardous Process Material (HPM) gases be enclosed in a secondary confinement and that the confinement be swept with air at a specified velocity, depending on the type of gas in the system.
Early gas delivery systems were rather large. Such early systems typically included various tubing connections extending between process gas holding tanks and tooling stations. More recent gas delivery systems have been made smaller and more compact by implementing various design changes. For instance, the use of tubing connections to carry process gas has been greatly reduced in some systems. Instead, passageways for process gas are drilled directly into a solid block of metal, often referred to as a panel. Components, such as valves, filters, mass flow controllers, and the like, are then mounted on the surface of the panel. By stacking such components together, a dense package is formed. Systems of this type are commonly referred to as "integrated gas panel systems" (IGP) or "integrated gas systems" (IGS).
In spite of the advantages offered by integrated gas panel systems, certain undesirable features have arisen. Particularly, the densely packaged components on the panel surface can present an impediment to the flow of purging gas. Thus, it has become difficult to efficiently purge leaked process gas residing along the component-panel interface.
As indicated above, in prior attempts at removing leaked process gas, a stream of purging gas (usually air) has been directed through the confinement enclosure over the surface interface whereat the panel meets the various components. In some constructions, fins have been utilized to assist in localizing the purging gas flow. When servicing the confinement enclosure, however, the flow is disrupted by the change in pressure caused by the door being open. In this condition, leaked process gas could flow out of the confinement enclosure through the open door.
Other conventional methods use spraying devices, as well as fans, to localize flow. But these, too, suffer from inadequate removal of leaked process gas, as well as loss of leaked process gas to the external environment when the confinement structure's door is opened.
It is, therefore, an object of this invention to provide an improved apparatus which permits the efficient purging of leaked process gas at the component-panel interface in an integrated gas panel system.
It is also an object of this invention to provide a method for efficiently purging process gas which might leak out at the component-panel interface in an integrated gas panel system.